* Hi guys.. Before opening an issue, I just wanted you to confirm that I am not doing something stupid here..

I have this repro case

```rust
#[derive(Debug, Deserialize)]
#[serde(untagged)]
enum F64 {
    F(f64),
}

#[test]
fn deserialize_proto_slice() {
    let n = r#"1.69234125E12"#;

    dbg!(serde_json::from_str::<f64>(n).unwrap());
    dbg!(serde_json::from_str::<F64>(n).unwrap()); // FAILS `Error("data did not match any variant of untagged enum F64", line: 0, column: 0)`
}
```

It works to deserialize the string to `f64` directly, but it fails to deserialize to a newtype wrapper with `untagged`.. Am i overlooking something?

`serde_json v1.0.105`, `serde v1.0.185`, `rustc 1.73.0-nightly (d06ca0ffa 2023-08-18)`